This invention relates generally to a method for producing slabstock polyurethane foams and, more particularly, to the use of a polyol blend including a conventional unsaturated polyol, a graft polyol, and a very low unsaturated polyether polyol for the production of slabstock polyurethane foams.
Polyols are generally defined as compounds that include a plurality of hydroxyl groups. Polyols having at least two isocyanate-reactive hydrogen atoms, particularly polyether polyols, are useful when combined with polyisocyanates to form polyurethanes. Polyols can be combined with polyisocyanates in the presence of catalysts and blowing agents to form either rigid or flexible foams. Flexible polyurethane foams are distinct from rigid foams. Flexible foams typically have a limited resistance to an applied load, are open-celled, permeable to air and are reversibly deformable. Flexible foams can either be formed in a discontinuous molding process or through a continuous slabstock process. In the continuous slabstock process, typically, the components are rapidly mixed together and extruded onto a moving bed reactor where the foam is permitted to freely rise to its final height. After the foam has fully risen it is processed to the desired final dimensions. Flexible foams are particularly useful in seating applications, carpet padding and other applications requiring reversible deformation of the foam.
Two important properties of flexible slabstock foam are its indentation force deflection and resilience. Many current flexible slabstock foam formulations suffer from less than ideal indentation force deflection and resilience properties. It would be advantageous to provide a flexible slabstock formulation having improved indentation force deflection and resilience properties